INTRODUCTION: Mechanical efficiency(ME) may be a contributing factor in running performance. ME is the ratio between the amount of mechanical work performed and the amount of energy expended during exercise. PURPOSE: The purpose of this investigation was to determine the possible differences in ME and percent changes in ME with repetitive hopping between competitive and recreational long distance runners. METHODS: Nine male runners (age 20±1.05yrs; height 69.69±3.3in; weight 70±14.9kg) who ran at least 3 days a week were recruited. Participants reported to the lab on 2 days, separated by 1 week. On the first day, height, weight, and VO2max were measured. On the second day, participants completed 10 minutes of hopping on a force plate to determine ME. Subjects were classified as ‘recreational’ (Rec) or ‘competitive’ (Comp) based on their self reported 1600m time and their VO2 max (rec: VO2max<60.0 ml/kg/m, 1600 time≥5:00; com: VO2max≥60.0 ml/kg/m, 1600m time<5:00). RESULTS: The recreational group had a mean VO2max of 51.9±1.57 ml/kg/m, ME of 38.7±7.00%, and % change in ME of 29.9±16.6%. The competitive group had a mean VO2max of 64.1±3.8, ME of 43.29±9.45%, % change in ME of 14.6±5.17%. Percent change in ME between groups trends toward significance (p=0.14). A correlation was observed between VO2max and % change in ME that trended toward significance (r=-0.58, p=0.10). PRACTICAL APPLICATION: It appears that individuals categorized as competitive may maintain ME better than recreational runners (i.e. lower % change in ME). The ability to maintain ME during long duration stretch-shortening cycle exercise may be a factor pertaining to running performance.
Listed In: Biomechanics